CHARACTERIZATION OF HEAT-SHOCK RESPONSE OF THE MARINE BACTERIUM VIBRIO-HARVEYI

We have investigated heat-shock response in a marine bacterium Vibrio harveyi. We have found that 39 degrees C was the highest tempature at which V. harveyi was able to grow steadily. A shift from 30 degrees C to 39 degrees C caused increased synthesis of at least 10 proteins, as judged by SDS-PAGE, with molecular masses of 90, 70, 58, 41, 31, 27, 22, 15, 14.5 and 14 kDa. The 70, 58, 41 and 14.5 kDa proteins were imm unologically homologous to DnaK, GroEL, DnaJ and GroES heat-shock prot eins of Escherichia coil, respectively. V. harveyi GroES protein had a lower molecular mass (14.5kDa) than E. coli GroES, migrating in SDS-P AGE as 15 kDa protein. We showed that a protein of similar to 43 kDa, immunologically reactive with antiserum against E. coli sigma 32 subun it (sigma(32)) of RNA polymerase, was induced by heat-shock and co-pur ified with V. harveyi RNA polymerase. These results suggest that the 4 3 kDa protein is a heat-shock sigma protein of V. harveyi. Preparation containing the V. harveyi sigma 32 homologue, supplemented with core RNA polymerase of E. coli, was able to transcribe heat-shock promoters of E. coli in vitro.